Merge pull request #16131 from CyrusNajmabadi/parserDiagnostics8

Don't report parse errors for modifiers on event accessors.

src/Compilers/CSharp/Portable/Parser/LanguageParser.cs

@@ -3590,14 +3590,7 @@ private enum PostSkipAction
                 this.ParseAttributeDeclarations(accAttrs);
                 this.ParseModifiers(accMods);
 
-                if (isEvent)
-                {
-                    if (accMods != null && accMods.Count > 0)
-                    {
-                        accMods[0] = this.AddError(accMods[0], ErrorCode.ERR_NoModifiersOnAccessor);
-                    }
-                }
-                else
+                if (!isEvent)
                 {
                     if (accMods != null && accMods.Count > 0)
                     {

src/Compilers/CSharp/Portable/Symbols/Source/SourceCustomEventAccessorSymbol.cs

@@ -85,6 +85,11 @@ internal sealed class SourceCustomEventAccessorSymbol : SourceEventAccessorSymbo
             }
 
             _name = GetOverriddenAccessorName(@event, isAdder) ?? _name;
+
+            if (syntax.Modifiers.Count > 0)
+            {
+                diagnostics.Add(ErrorCode.ERR_NoModifiersOnAccessor, syntax.Modifiers[0].GetLocation());
+            }
         }
 
         internal AccessorDeclarationSyntax GetSyntax()

src/Compilers/CSharp/Test/Syntax/Parsing/ParserErrorMessageTests.cs

@@ -4053,8 +4053,13 @@ public static int Main()
     }
 }
 ";
-
-            ParseAndValidate(test, Diagnostic(ErrorCode.ERR_NoModifiersOnAccessor, "private"), Diagnostic(ErrorCode.ERR_NoModifiersOnAccessor, "public"));
+            CreateCompilationWithMscorlib(test).GetDeclarationDiagnostics().Verify(
+                // (17,9): error CS1609: Modifiers cannot be placed on event accessor declarations
+                //         private add{}
+                Diagnostic(ErrorCode.ERR_NoModifiersOnAccessor, "private").WithLocation(17, 9),
+                // (18,9): error CS1609: Modifiers cannot be placed on event accessor declarations
+                //         public remove{}
+                Diagnostic(ErrorCode.ERR_NoModifiersOnAccessor, "public").WithLocation(18, 9));
         }
 
         [Fact]
@@ -4072,7 +4077,13 @@ public class Test
 }
 ";
 
-            ParseAndValidate(test, Diagnostic(ErrorCode.ERR_NoModifiersOnAccessor, "public"), Diagnostic(ErrorCode.ERR_NoModifiersOnAccessor, "private"));
+            CreateCompilationWithMscorlib(test).GetDeclarationDiagnostics().Verify(
+                // (7,9): error CS1609: Modifiers cannot be placed on event accessor declarations
+                //         public add { }
+                Diagnostic(ErrorCode.ERR_NoModifiersOnAccessor, "public").WithLocation(7, 9),
+                // (8,9): error CS1609: Modifiers cannot be placed on event accessor declarations
+                //         private remove { }
+                Diagnostic(ErrorCode.ERR_NoModifiersOnAccessor, "private").WithLocation(8, 9));
         }
 
         [WorkItem(863423, "DevDiv/Personal")]